<!DOCTYPE HTML>
<html>
<body>
<script type="text/javascript">
function check(){

  alert("event.keyCode=="+event.keyCode)
}

</script>

<input onkeydown="check();"/><br />

</body>
</html>
<!--
<html>
<head>
    <script type="text/javascript" src="/jquery/jquery.js"></script>
    <script type="text/javascript">
$(document).ready(function(){
  $("input").bind("keypress",function(){
    alert("event.keyCode=="+event.keyCode)
  });
});
</script>
</head>
<body>
<p>This is a paragraph.</p>
<input/>
</body>
</html>

<html>
<head>
    <script type="text/javascript" src="/jquery/jquery.js"></script>
    <script type="text/javascript">
$(document).keydown(function(event){
　　　　
　　　　　　alert('你按下了Enter  event.keyCode='+event.keyCode);
　　　　
　　});
</script>
</head>
<body>
<p>This is a paragraph.</p>
<input/>
</body>
</html>
-->